<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .head {
            height: 100px;
            background-color:red
        }
        .adv{
            height: 150px ;
            background-color: pink
        }
        .mid{
            margin-top: 20px;
            margin: 0 auto;
            height: 500px;
            background-color:blue
        }
        .left{
            width: 200px;
            height :90%;
            float: left;
            background-color:yellow
        }
        .right{
            width: 500px;
            height: 90%;
            float: right;
            background-color: green
        }
        .footer{
            height: 200px;
            background-color: #000000;
        }
    </style>
</head>
<body>
    <div>
        <div class="head">头部</div>
        <div class="adv">广告</div>
        <div class="mid">
            <div class="left">左</div>
            <div class="right">右</div>
        </div>
        <div class="footer"></div>
    </div>
</body>
</html>